Vacuum insulating glass (VIG) units typically include at least two spaced apart glass substrates that enclose an evacuated or low-pressure space therebetween, The substrates are interconnected by a peripheral edge seal and typically include spacers between the glass substrates to maintain spacing between the glass substrates and to avoid collapse of the glass substrates that may be caused due to the low pressure environment that exists between the substrates. Some example VIG configurations are disclosed, for example, in U.S. Pat. Nos. 5,664,395, 5,657,607 and 5,902,652, the disclosures of which are all hereby incorporated by reference herein in their entireties.
FIGS. 1 and 2 illustrate a typical VIG unit 1 and elements that form the VIG unit 1. For example, VIG unit 1 may include two spaced apart glass substrates 2, 3, which enclose an evacuated or low-pressure space 6 therebetween. Glass sheets or substrates 2,3 are interconnected by a peripheral edge seal 4 which may be made of fused solder glass, for example. An array of support pillars/spacers 5 may be included between the glass substrates 2, 3 to maintain the spacing of substrates 2, 3 of the VIG unit 1 in view of the low-pressure space/gap present between the substrates 2, 3.
A pump-out tube 8 may be hermetically sealed by, for example, solder glass 9 to an aperture/hole 10 that passes from an interior surface of one of the glass substrates 2 to the bottom of a recess 11 in the exterior surface of the glass substrate 2. A vacuum is attached to pump-out tube 8 to evacuate the interior cavity 6 to a low pressure. After evacuation of the cavity 6, the tube 8 is melted to seal the vacuum. Recess 11 retains the sealed pump-out tube 8. Optionally, a chemical getter 12 may be included within a recess 13 that is disposed in an interior face of one of the glass substrates, e.g., glass substrate 2.
VIG units with fused solder glass peripheral edge seals 4 are typically manufactured by depositing glass frit, in a solution, around the periphery of substrate 2. This glass frit ultimately forms the glass solder edge seal 4. A second substrate 3 is brought down on substrate 2 so as to sandwich spacers/pillars 5 and the glass frit solution between the two substrates 2, 3, The entire assembly including the glass substrates 2, 3, the spacers or pillars 5 and the seal material (e.g., glass frit in solution), is then heated to a temperature of at least about 500° C., at which point the glass frit melts, wets the surfaces of the glass substrates 2, 3, and ultimately forms a hermetic peripheral or edge seal 4.
After formation of the edge seal 4, a vacuum is drawn via the pump-out tube 8 to form low pressure space 6 between the substrates 2, 3. The pressure in space 6 may be produced by way of an evacuation process to a level below atmospheric pressure, e.g., below about 10−2 Torr. To maintain the low pressure in the space or cavity 6, substrates 2, 3 are hermetically sealed. Small high strength spacers or pillars 5 are provided between the substrates to maintain separation of the approximately parallel substrates against atmospheric pressure. Once the space 6 between substrates 2, 3 is evacuated, the pump-out tube 8 may be sealed, for example, by melting using a laser or the like.
The pump-out tube 8 is often located in a corner of one of the substrates, such as, for example, illustrated in FIGS. 1 and 2. The pump-out tube 8 may be made of glass and may protrude above a surface of the glass substrate in which it is located to facilitate pumping and subsequent melting. Because the pump-out tube 8 is typically made of glass and extends above a surface of the substrate it is quite fragile and susceptible to damage. To address this and other fragility problems, protective caps are sometimes placed over the tubes after evacuation and melting. There are a number of protective cap configurations and mounting methods. Some arrangements suffer from drawbacks such as those identified in U.S. patent application Ser. No. 13/246,980 incorporated by reference above.
Additionally, a number of newly developed VIG configurations have been developed. According to some of these configurations, a VIG unit 1, such as, for example, described above with reference to FIGS. 1 and 2, may be provided with an additional laminated sheet or substrate that may be disposed, for example, on or over a substrate that includes a pump-out port. The additional laminated sheet may be adhered to one of the substrates of a conventional VIG unit by means of a laminating adhesive in the form of a laminating film of or including a polymer based adhesive, such as, for example, PVB, or the like.
Additional problems arise with respect to treatment of the pump-out tube in VIG configurations that have an additional substrate laminated thereon. For example, when laminating an additional substrate on a side of the VIG unit where the pump-out port is located, the laminated additional substrate and the laminating film must be provided with a hole to accommodate the protruding pump-out tube. The hole must be of a diameter to provide sufficient clearance about the pump-out tube when the laminated substrate and laminating film are disposed over the substrate of the VIG unit. Due to manufacturing tolerances when creating the hole, as well as the subsequent placement of a protective cap, there is a chance that the holes and the protective cap will not be concentrically or even substantially concentrically aligned. In addition, a glass edge of the access hole formed in the additional laminated substrate could have a rough edge. Both of these factors, e.g., poor registration of the hole and a possible protective cap, and the rough edge around the access hole in the laminated substrate, contribute to an undesirable aesthetic appearance of the final laminated VIG unit.
One possible solution may be to just place the cap over the hole in the additional laminated substrate after the lamination process that provides the laminated substrate on the underlying VIG unit to form a laminated VIG unit. However. this proposed solution suffers from numerous drawbacks. For example, as noted above, the pump-out tube is fragile, and is exposed during the lamination process, thus making it even more susceptible to damage during the lamination process. Another solution may be to simply place a second cap over the first cap at the conclusion of the lamination process. This solution also suffers from a number of drawbacks including, for example, that the resulting laminated VIG unit will exhibit a significant amount of stack-up height in the area of the stacked protective caps.
According to certain example embodiments disclosed herein, there may be included a process protection ring around the pump-out tube prior to the lamination process. This may be possibly be done in combination with any of the other possibilities discussed above. During the lamination process, the process protection ring provides a barrier that protects the pump-out tube from damage that might occur during the lamination process. For example, if the edge of the hole formed in the laminating film and/or the laminated substrate engages the pump-out tube, such force may break or damage the pump-out tube. In the case where a process protection ring is provided around the exposed portions of the pump-out tube, the forces that would otherwise have impacted the pump-out tube, are absorbed by the process protection ring, thereby mitigating potential damage to the pump-out tube. In this connection the height of the process protection ring may be sufficient to provide protection to the exposed portions of the pump-out tube. According to certain example embodiments, it may be preferable for a height of the process protection ring to be about the same height of the sealed pump-out tube. Alternatively, the process protection ring may have a lower or slightly lower height than the sealed pump-out tube so long as the process protection ring is of sufficient height to provide protection to the pump-out tube. It may also be preferable, according to certain example embodiments, that the height of the process protection ring not be substantially greater than a height of the sealed pump-out tube, so as to avoid additional stack-up height with the finished protective cap.
Additionally, by providing a process protection ring, the need for providing a cap during the lamination process is reduced and could possibly be eliminated in certain example non-limited embodiments. Thus, after the lamination process, a single cap may be disposed over the holes in the laminating film and laminated substrate that were provided to accommodate the protruding pump-out tube. A further advantage of providing a single opaque or substantially opaque protective cap over the pump-out tube, process protection ring and hole(s) in the laminating film and laminated substrate, in certain example embodiments, is that the single outer protective cap covers the holes and exposed edges thereof. and therefore provides a more desirable aesthetic appearance by covering any potential misalignment or non-concentric arrangement of the pump-out tube and hole(s) that may otherwise be visible.
According to further example embodiments, the protective cap may be further provided with at least one positioning ridge disposed about a periphery of the side of the cap that faces the laminated glass substrate, such that the ridge may engage an interior edge of the hole formed in the laminated substrate. This positioning ridge provides additional protective strength for the protective cap and may further reduce the amount of movement of the protection cap once placed over the hole in the laminated substrate. In addition, it may also be advantageous to provide a protective cap having a lower profile than conventional protective caps to improve the aesthetic appearance of the laminated VIG unit.
To provide these and other advantages, there is an example vacuum insulated glass (VIG) assembly, comprising: first and second substantially parallel spaced apart substrates; a peripheral edge seal disposed about a periphery of said first and second spaced apart substrates, the edge seal and first and second substrates defining a cavity therebetween; a pump-out tube extending from an inner surface of said first substrate adjacent said cavity, through said first substrate and extending beyond an outer surface of said first substrate; and a protective ring disposed about a portion of said pump-out tube extending beyond an outer surface of said first substrate.
According to further example embodiments, a laminated vacuum insulated glass assembly is provided, an example laminated vacuum insulated glass assembly, comprising: first and second substantially parallel spaced apart substrates; a peripheral edge seal disposed about a periphery of said first and second spaced apart substrates, the edge seal and first and second substrates defining a cavity therebetween, said cavity being evacuated to a pressure less than atmospheric pressure; a pump-out tube extending from an inner surface of said first substrate adjacent said cavity, through said first substrate and extending beyond an outer surface of said first substrate; a protective ring disposed about a portion of said pump-out tube extending beyond an outer surface of said first substrate; a third substrate laminated over said first substrate, said third substrate including an opening into which a portion of said pump-out tube and said protective ring extend; and a cap disposed over said opening in said third substrate.
Certain example methods for making a vacuum insulated glass assembly according to certain example embodiments are also provided, example methods comprising: providing a first glass substrate; disposing a plurality of spacers on said first substrate; depositing an edge seal material along substantially a periphery of a first surface of said first substrate; providing a second glass substrate over said first glass substrate sandwiching said spacers and edge seal material therebetween; heating said first and second glass substrates and said edge seal material to form a hermetically scaled cavity between said first and second substrates; evacuating said cavity via a pump-out tube provided in one of the first and second glass substrates; sealing said pump-out tube by melting a portion thereof; disposing a protective ring over one of said first and second glass substrates and surrounding a portion of said pump-out tube, said protective ring being adhesively coupled to one of said first and second glass substrates; laminating a third glass substrate over said first or second substrate through which a portion of said pump-out tube extends; and providing a cap over an opening in said third glass substrate in which said protective ring and a portion of said pump-out tube are disposed.
These and other embodiments and advantages are described herein with respect to certain example embodiments and with reference to the following drawings in which like reference numerals refer to like elements, and wherein: